Feeding mechanism for rock drills



' mwss FP M91936., J. c. CUR-ris FEEDING MECHANISM FOR ROCK DRILLS Filed June 27, 1934 .VM Sm.

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JOHN 6. CUE-776 INVENTOR Patented Feb. 11, 1936 UNITED STATES PATENT OF F I CE The Cleveland Rock Drill Company, Cleveland, Ohio, a corporation of0hio Application June 27, 1934, Serial No. 732,698

Claims.

This invention relates broadly to rock drills, but more particularly to feeding mechanism for rock drills of the drifter type.

One object of this invention is to produce a 5 mechanism wherein the jars or vibrations imparted to the drill during its normal operation are utilized for feeding the drill toward or away from the work.

Another object of this invention is to provide a rock drill with a feeding mechanism operated by the jars imparted to the rock drill during its normal operation, and having means for locking the drill against relative longitudinal movement with respect to its support irrespective of the jars imparted to the drill.

Other objects and advantages more or less ancillary to the foregoing reside in the specic construction and aggroupment of the elements peculiar to this structure, as will become apparent from a more complete examination of this specification.

In the drawing which illustrates the invention:

Fig. 1 is a longitudinal View partly in section of a rock drill embodying the invention.

Fig. 2 is an enlarged longitudinal sectional view of the feed control mechanism shown in Fig. 2.

Figs. 3 and 4 are views similar to Fig. 2 with the throttle valve shown in different positions.

Referring to the drawing in which like symbols designate corresponding parts throughout the several views, i@ represents a fluid actuated rock drilling motor comprising a cylinder II having the lower portion thereof formed with the usual longitudinally -disposed guides I2. To the front end of the cylinder is secured a chuck housing I3 adapted to receive the drill steel I4 upon which the hammer which is reciprocably mounted within the cylinder Il is capable of delivering its blows. To the rear end of the cylinder is secured the usual back head I5 having afxed thereto a pressure fluid inlet connection I6.

Located below the rock drill I0, there is a feed` tube I1 having the upper wall thereof formed 45 with guide Ways I8 within which the guides I2 of the cylinder Il are slidably mounted. The lower wall of the feed tube is provided with the conventional cone I 9 by which the assembly may be aiiixed to a rock drill supporting frame such 50 as a tripod or the like.

Secured within the rear end of the feed tube I1, there is a throttle valvehousing 29 formed with a throttle valve chamber 2| having a throttle valve 22 rotatable therein, and formed with 55 a stem 23 protruding through a nut 24 which is secured in screw tight engagement within the open end portion of the throttle valve chamber 2|. To the stem 23 is secured a handle 25 by which the throttle valve 22 may be operated. 6.0, The throttle valve 22 is formed with a bore or (Cl. 25E-45) valve chamber 26 having `the bottom thereof properly machined to constitute a valve seat '21. Slidably Vmounted Within the bore v26, there is a plate valve 28 which is constantly urged against the yseat 2l `by the effort of a-compression spring 5 29. Outside the marginal edge of the valve seat 2l, the plate valve is provided with a plurality of relatively small ports 30. Leading from the valve chamber 2| into the rear end of the feed tube I1 via a passage 3l, there is a duality of ports 32 and 33, while the front end of the feed tube is capable of communication with the valve chamber 26 through the passages 34, 35, andV 36. Leading from the `center Yof valve seat 21, there is a passage 37 capable of communication with either the port 33 or :35, while the bore `26 of the throttle valve V22 `is also capable of communication with either the port `32 or 36 through a radially disposed port 38.

Secured within `the feed tube I 'I at a place substantially equidistant from the ends thereof, there is a partition 39 formed with a centrally disposed bore through which is slidably and rotatably mounted a relatively long tubular member 49, which has its -left 'internal end portion threaded as at 4I for engagement with a screw 42 secured in screw threaded engagement Iwithin the throttle valve-housing 2l) and maintained therein against relative rotation by means of a lock nut 43. Mounted onfthe Afree end portion of the tubular member 40, isa piston 44 comprising a duality of packing members 45 clamped between a shoulder 46, which is formed on the tubular member 45, and a nut 41. Within the partition 39 is also mounted a packing 48 engageable with the tubular member 49 for the purpose which will be explained later. Depending from the front housing i3, there is a lug 49 extending into the feed tube through a longitudinally disposed slot 50 formed within the upper wall of a portion yof the feed tube which extends `from the partition 39 to thefront end thereof. 'Ihe lug 49 is provided with a screw threaded bore adapted to receive, in screw threaded engagement therewith a screw 5I which is integrally afxed at one end of the tubular member 4Q. The screw 5I is formed :of a right hand thread while the screw 42 is formed with a left hand thread. The feed tube I1 between the partition 40 and the throttle valve housing 20 together with all the passages heretofore recited, is lled with non-compressible liquid such as oil, which Amay be poured therein by removing the filler plug 52 normally `secured in screw threaded engagement -within the throttle valve housing 2U.

Theoperation of the device is as follows: When pressure fluid is admitted into the cylinder II of the rock drill to cause the reciprocation of the hammer therein, the jars resulting from the reversal of the stroke of the hammer are transmitted -to the rock drill, thus causing a recipro 60 catory or longitudinal vibratory motion of the rock drill relative to the support or tube l1. Due to the engagement of the right hand screw 5I with the internal threads of the lugs 49, the vibratory motion of the rock drill will cause the oscillatory motion of the screw and the conseqential oscillatory motion of the tubular member 49. The engagement of the internally screw threaded portion 4l of the member 40 with the stationary left hand screw 42 will transform the oscillatory motion of the member 49 in a reciprocatory motion of the latter, which is transmitted to the piston 44 by its connection with the member 49. Assuming Ythe throttle valve 22 to be positioned as illustrated in Fig. 2, the longitudinal movement imparted to the tubular member 49 and consequently tothe piston 44 in the direction away from the throttle valve housing 29, will cause the non-compressible fluid between the piston and the partition 39 to be displaced through the passages 34, 35, and 31. The pressure exerted on the fluid by the longitudinal movement of the piston will cause the plate valve 28 to separateV from Yits seat 21, thus allowing the flow of the fluid intoV the throttle valve chamber 2E via the restricted ports 38 formed in the plate valve 28. From the throttle valve chamber 26, the fluid is readmitted into the tube I'l between the throttle valve housing 29 and the piston 44, through the throttle valve port 38, and ports 32 and 3l. The longitudinal movement of the tubular member 4U and piston 4.4 toward the housing 20 is prevented by the non-compressible fluid within the portion of the tube Il adjacent the housing 29, since the fluid tending to escape therefrom is either arrested by the throttle valve 22 covering the port 33, or the platevalve 28 covering the port 3l. In this instance, it will be understood that the noncompressible fluid within the tube l1 is displaced from the front portion of the cylinder into the rear portion thereof, thus permitting the forward step by step movement of the rock drill, while the rearward motion of the latter is prevented by the non-compressible uid precluding the rearward movement of the piston v44.

When it is desired to feed -the rock drill rearwardly or away from the work, the throttle valve may be positioned as illustrated in Fig. 4. In this instance, the longitudinal movement of the rock z drill away from the work, which is imparted thereto due to the reversal ofthe stroke of the hammer reciprocating within the cylinder l l, is transmitted to the piston 44 through the screw 5l and tubular member 49. The movement of the piston `toward the throttle valve housing 29 will cause the non-compressible iluid within the portion of the tube Il adjacent the housing 20 to be displaced therefrom through the ports 3|, 33 and 31, The pressure exerted on the fluid by the piston 44 will be sufficient to cause the separation of the plate valve 23 from its seat 2l, thus permitting the flow of the fluid into the throttle valve chamber 23 from whereit will be readmitted into the front end of the tube Il through the throttle valve port 38, ports 36, 35, 34. The longitudinal movement of the piston 44 and tubular member 49 away from the throttle valve housing 2l] is now prevented by the non-compressible fluid within'the portion of the tube l1, adjacent the partition 39. The fluid tending to escape therefrom, is either arrested by the throttle valve 22 covering the port 35, or by the plate valve covering the port 31. With the throttle valve in the position illustrated in Fig. 4, it will now be understood that the vibratory longitudinal movement imparted to the screw S and transmitted to the tubular member 40 and p-iston 44, will cause the feeding motion of the rock drill away from the work.

When the throttle valve is positioned as illustrated in Fig. 3, the rock drill is locked against longitudinal movement in both directions. The non-compressible fluidwithin the tube I1 is prevented to escape therefrom through the ports 3l or 34, since these ports or the ports connected thereto, are closed by the throttle valve 22. In this instance the rock drill may be actuated without imparting a feeding motion thereto, thus permitting the operator to start the hole to be drilled while the rock drill remains stationary.

, In the present construction, since the'lead of the left hand screw 42 is equal to the lead ofthe right hand screw 5l, the travel of the piston 44 will be only one half ofthe corresponding travel of therock drill. Y

The packings 45, associated with the piston 44, are constantly subjected to the action of the non-ccmpressible fluid thereon to` afford-a fluid tight joint with the inner wall of the tube 1, while the packing 48 Within the partition 39 is Vconstructed in a manner adapted to retain any fluid which may escape from the tube I1 between the tubular member 40 and the partition 39.

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not to be restrictive or confining and it is to be further understood that various rearrangements of parts and modification of structural detail may be resorted towithout departing from the scope or spirit of the invention as herein claimed.

I claim: Y Y l 1. In a feeding device, the combination with a support and a motor slidable thereon, a hammer L.

reciprocable within said motor imparting jars thereto to reciprocate the motor relatively to theV support, of a tube having a piston reciprocable therein, a connection between said motor and said piston for transmitting the'reciprocation of the former to the latter, non-compressible fluid within said tube on both sides of said piston normally displaced within the former due to the reciprocatory movement of the latter, and means for selectively controlling the displacement of the fluid i,

within said tube in a manner preventing the movement of said piston and consequently of said motor in one or the other direction. e

2. In a feeding device, the combination with a support and a motor slidable thereon, a hammer within said motor imparting forward and backward longitudinalV motion thereto relative to the support, a stationary housing, an element within said housing connected to said motor for longitudinal motion therewith;non-compressible fluid within said housing normally displaced therein due to the longitudinal movement ofsaid element in either direction, and means for selectively controlling the displacement ofV the uid within said housing in Ya manner preventing the movement f; L

of saidelement and consequently of said motor Y in one or the other direction. A

3. In a transmission mechanism, a power actuated motor having vibrations imparted thereto,

a housing having a membermovable therein, connecting means between said motor and said member for transmitting the vibrations of the former to the latter at a different rate of amplitude, noncompressible fluid within said housing normally displaced therein by virtue of the vibrations of Cil said member, and means for controlling the displacement of said non-compressible fluid within said housing in a manner whereby said member and consequently said motor are free to move in one direction and are locked against movement in the other direction.

4. In a feeding device, the combination with a support and a motor slidable thereon, a hammer reciprocable within said motor imparting jars vthereto to reciprocate the motor relative to the support, of a housing having a piston reciprocable therein, an elongated member connecting said piston to said motor, said member having an internal and an external screw threaded portion, an internally screw threaded lug depending from said motor adapted to receive the external portion of said screw for transforming the reciprocation of said motor in a rotary motion of said member, a stationary screw within said housing engageable with the internal screw threaded portion of said member for transforming the rotary motion of the latter in a longitudinal motion thereof transmitted to said piston, and non-compressible fluid within said housing acting on said piston for locking the latter against longitudinal movement in one direction, causing thereby the :lars imparted to said motor to produce an intermittent longitudinal movement of the latter in one direction.

5. In a feeding device, the combination with a support and a motor slidable thereon, a hammer reciprocable within said motor imparting jars thereto to reciprocate the motor relative to the support, of a housing having a piston reciprocable therein, an elongated member connected to said piston, interengaging means on a portion of said member and within said motor for transforming the reciprocatory motion of the latter in a rotary motion of said member, means within said member engageable with stationary means within said housing for transforming the rotary motion of the former in a longitudinal motion thereof, said last mentioned motion being transmitted to said piston by its connection with said member, and non-compressible fluid within said housing acting on said piston for locking the latter against longitudinal movement in one direction, causing the jars imparted to said motor to produce an intermittent longitudinal movement of the latter in one direction.

6. In a feeding device, the combination with a support and a motor slidable thereon, a hammer reciprocable within said motor imparting jars thereto to reciprocate the motor relative to the support, of a cylinder having a piston reciprocable therein, an elongated member connected to said piston, said member being formed of a tubular portion having a smooth external surface movable in and out of said cylinder and of an externally screw threaded portion operatively engageable with said motor for transforming the reciprocatory motion of the latter in a rotary motion of said member, means within said tubular portion associated with stationary means within said cylinder for transforming the rotary motion of said member in a longitudinal motion of the latter, said last mentioned motion being transmitted to said piston by its connection with said member, non-compressible fluid within said cylinder acting on said piston for locking the latter against longitudinalmovement in one direction, causing thereby the jars imparted to said motor to produce an intermittent longitudinal movement of the latter in one direction, and a packing engaging the external surface of said member for preventing the escape of said non-compressible fluid from said cylinder.

7. In a feeding device, the combination with a support and a motor slidable thereon, a hammer reciprocable within said motor imparting longitudinal forward and backward motion thereto relative to the support, a housing having an element slidable therein, said element being connected to said motor for longitudinal motion therewith, non-compressible fluid within said housing on both sides of said element normally displaced from one tothe other side thereof due to the longitudinal motion of said element, and means movable in time relation with the longitudinal movement of said element in one direction for permitting the displacement of the fluid from one to the other side of said element but preventing the reversed displacement of said fluid.

8. In a feeding device. the combination with a support and a motor slidable thereon, a hammer reciprocable within said motor imparting longitudinal forward and backward movements thereto relative to the support, a housing having an element slidable therein, said element being connected to said motor for longitudinal movements therewith, non-compressible fluid within said housing normally displaced therein from one to the other side of said element, means operable for permitting the displacement of the fluid in one direction at the exclusion of the other, and manually operable means for selectively controlling the direction of displacement of said iluid and thereby controlling the direction of longitudinal movement imparted to said motor.

9. In a feeding device, the combination with a support and a motor slidable thereon, a hammer reciprocable within said motor imparting alternative forward and backward longitudinal movements thereto, a housing having an element slidable therein connected with said motor forl longitudinal movement therewith in both directions, non-compressible fluid within said housing normally displaced therein due to the longitudinal movements of said element, means preventing the displacement of the iluid normally resulting from the longitudinal movement of said element in one direction and permitting the displacement of the fluid resulting from the longitudinal movement of said element in the other direction, thereby allowing a step by step longitudinal movement of said motor in one direction, and means for selectively controlling the sense of direction of said last longitudinal movement.

10. In a feeding device, the combination with a support and a motor slidable thereon, a hammer reciprocable within said motor imparting alternative forward and backward longitudinal movements thereto, a housing having an element slidable therein connected with said motor for longitudinal movement therewith in both directions, non-compressible iluid within said housing normally displaced therein due to the longitudinal movements of said element, a mechanism automatically operable for controlling the displacement of the fluid within said housing in a manner preventing the longitudinal movement of said motor in one direction, thereby causing the longitudinal movements imparted to said motor in the other direction to effect a step by step feeding motion of the latter in said last direction,

JOHN C. CURTIS, 

